Abstract
Creating a secure and comfortable linkage between the residual limb and prosthetic socket in persons with lower limb amputation is a critical factor for successful rehabilitation, including ambulation and other activities of daily living. Unwanted rotation within the socket can be a clinical problem for prosthesis users. One way of addressing issues experienced with transverse plane control of the socket may be through increased friction interface forces. It has been proposed that friction at the residual limb/socket interface may be increased by adding texture to interface components. Three-dimensional (3D) printing may be used to fabricate sockets with texture patterns added to the inner socket surface. Hence, the aim of this study was to investigate the effects of socket texturing on transverse plane rotation of the socket on a mock residual limb under two suspension conditions: passive suction and active vacuum. To conduct this study, we developed a mechanical testing protocol as no standardized tests currently exist to assess prosthetic sockets. Sockets with 14 different texture patterns were fabricated using the Squirt-Shape™ 3D printer. Textured sockets were compared to an Original Squirt-Shape (OSS) socket and a smooth thermoformed socket. Sockets were fitted with a mock residual limb and bi-axially loaded to 350 N compression with simultaneous rotation (2.5', 5' and 7.5') using a custom rotation assembly attached to a uniaxial hydraulic material testing system. There was a statistically significant three-way interaction between suspension, angle and texture (p < 0.0005). Torques between textured and reference sockets, for all rotation angles and both suspension conditions, were significantly different (p < 0.0005). Using newly developed testing protocols, it was demonstrated that some texture patterns significantly increased torque (i.e., resistance against unwanted rotation) in the transverse plane compared to both OSS and smooth sockets, especially for passive suction. Rotation testing of sockets may provide insight into socket design to improve suspension in the transverse plane.
| Original language | English (US) |
|---|---|
| Article number | e0233148 |
| Journal | PloS one |
| Volume | 15 |
| Issue number | 6 |
| DOIs | |
| State | Published - Jun 2020 |
Funding
This work was supported by the Office of the Assistant Secretary for Health Affairs, through the Neuromusculoskeletal Injuries Research Award under Award No. W81XWH-16-1-0485. Opinions, interpretations, conclusions and recommendations are those of the author and are not necessarily endorsed by the Department of Defense (DOD). Prosthetic Design Inc. were funded by the DOD as a collaborative partner on this study. As a collaborative partner they provided support in the form of research materials (primarily printing of sockets). Additional roles in this study included developing the texture patterns, validating 3D printing processes, and contributing to preparation of the manuscript. Brad Poziembo is an employee of Prosthetic Design Inc., the commercial manufacturer of the Squirt-Shape™ 3D Printer used in this study. The DOD award provided support in the form of salaries for authors SF, BP, JY, and VS, but the funder did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. Author JQ was supported on a training grant from National Institute on Disability, Independent Living and Rehabilitation Research of the U.S. Department of Health and Human Services, Administration for Community Living (grants 90AR5010 and 90AR5031). Opinions, interpretations, conclusions and recommendations are those of the authors and are not necessarily endorsed by the U.S. Department of Health and Human Services. The specific roles of all authors are articulated in the 'author contributions' section. The authors wish to thank Frank Lantz and John Bussan from the Northwestern University Research Shop for their guidance in optimizing the design and fabrication of custom fixtures, and Dr. Matthew Major for his guidance with use of the Instron and statistical analyses.
ASJC Scopus subject areas
- General